Pain is a major symptom in many medical conditions and a common reason that prompts individuals to seek medical attention. Neuropathic pain is a type of pain that may arise as a consequence of a lesion or disease affecting the somatosensory system. Neuropathic pain is typically characterized by patients as burning, aching, or shooting. The pain may be provoked by normally innocuous stimuli (allodynia). It is also commonly associated with hyperalgesia (increased pain intensity evoked by normally painful stimuli) and abnormal sensations, such as pins-and-needles or electric-shock-like sensations. Neuropathic pain can be very severe and disabling and can result in significant functional, psychological, and/or social consequences.
Neuropathic pain has been estimated to affect up to 6%-8% of the general population. It can arise from a variety of causes that involve the brain, spinal cord, and/or peripheral nerves, including cervical or lumbar radiculopathy, diabetic neuropathy, postherpetic neuralgia, HIV-related neuropathy, and spinal cord injury, among others. Neuropathic pain can arise following physical injury, persisting despite resolution of the inciting damage to the nerve and the surrounding tissues.
Regardless of the underlying cause of neuropathic pain, common treatment goals are to decrease pain and/or improve function. Tricyclic antidepressants, anticonvulsants, and opioid analgesics are frequently prescribed. However, these medications frequently fail to provide adequate pain relief and/or are associated with troubling side effects. People with neuropathic pain have been found to generate 3-fold higher health care costs compared with matched controls. In the United States, health care, disability and related costs associated with neuropathic pain have been estimated at almost $40 billion annually.
There is a considerable need for more effective pharmacological therapies for neuropathic pain.